Magneto interrupter



NOV. 15, 1932. w SCHWARZMAN 1,887,522

MAGNETO INTERRUPTER Filed Feb. 25, 1950 INVENTOR WE. Saba/a1" an AllATTORNEY Patented Nov. 15, 1932 UNITED STATES PATENT OFFICE WOLFGANG E.SCHWARZMAN, OF LONGMEADOW, MASSACHUSETTS, ASSIGNOR TO AMER- ICAN BOSCHMAGNETO CORPORATION, OF SPRINGFIELD, MASSACHUSETTS, A COR- PORATION OFNEW YORK MAGNETO INTERBUPTER Application med February 25, 1930. SerialNo. 431,106.

My invention relates to improvements in circuit breakers orinterrupters, particularly interrupters of the type used on magnetos forigniting the combustible motive agent in the power chambers of internalcombustion engines.

An object of the invention is to provide an interrupter for a magneto ofsimple and inexpensive construction and comprising relatively few partswhich can be readily assembled or dismounted.

Another object of the invention is to provide an interrupter embracing apair of contacts mounted so as to be relatively movable and adapted toengage and disengage each other, one of the contacts being suitablyinsulated and connected in the circuit of the magneto by special meanswhich also acts to hold the contacts together.

A further object of the invention is to provide an interruptercomprising a breaker lever which is partly of insulation and partly ofconductive material, with a spring to maintain the lever in circuitclosing position, and at the same time connect the lever to the windingof the magneto controlled by the circuit breaker.

An additional object of the invention is to provide a circuit breaker orinterrupter comprising a movable lever that is retained in position by aholding element, such as a spring, which is movable to enable the leverto be quickly taken off when necessary.

Other objects and advantages of the invention will be made clear in thefollowing description and drawing, in which a preferred embodiment ofthe invention is illustrated. But this disclosure is explanatory only,and changes may be made in the interrupter herein set forth as regardsmatters of shape, size and arrangement of parts, with out going beyondthe principle of the invention or exceeding the scope and meaning of theterms in which the appended claims are expressed.

In the drawing, Fig. 1 is a side view of an interrupter according to myinvention; Fig.

2 is a front view thereof with lever in circuit-closmg positlon; Fig. 8is a fragmentary 59 front view showing the contacts separated;

Fig. 4 is a side view seen Fig. 2, for example showing the parts inposition for assembling; Fig. 5 is a front View with some of the partsin section; Fig. 6 is a perspective view of a block of insulationforming part of the interrupter lever; and Fig. 7 is a perspective viewof the conductive portion of the interrupter lever with the end of theoperating spring attached.

The same numerals identify the same parts throughout.

The numeral 1 indicates a supporting member or disc, which is of metaland is provided with a central bearing 2 to enable the interrupter to besecured to the forward trunnion or journal of the armature of anignition magneto of any well known design. The magneto may be of eitherthe high tension or low tension type and connection may be made betweenthe breaker and the ungrounded terminal of the low tension winding onthe armature through a bore or passage in the shaft or journal on whichthe bearing 2 is fitted. As usual, this shaft or journal will beprovided with a key to engage a keyway in the bearing 2, so that whenthe armature rotates, the circuit breaker will rotate with it. The disc1 has a projection 3 extending at right angles to its outer face at onepoint of the edge thereof, and this projection will have a threaded holeto receive and carry a screw 4, one end of which bears an electrode 5 ofsuitable material. The numeral 6 indicates the movable electrode, whichis mounted upon the breaker lever comprising the parts 7 and 8, theformer being a simple plate of metal and the latter a block ofinsulation to which the metal plate 7 is affixed. This breaker lever ismounted upon a pivot or journal 9 and moves on the journal as an axis tocause the electrodes 5 and 6 to come together or separate as thearmature and circuit breaker revolve. The disc 1 with its central hub orbearing 2, projection 3 and journal 9 may be all made in one piece.

A binding nut 10 is carried by the screw 4: on one side of theprojection 3. The head 11 bearing the electrode 5 on the opposite sideof from the left of 4 to adjust the electrode 5, and the nut may beemployed to secure the screw 4 in adjusted position.

The block of insulation 8 has a central bore 12 to receive the journal 9and a groove 13 extending across one end. At 14 is an opening for ascrew and the plate 7 has a cooperating opening 15. This plate may bebent transversely to provide a shoulder 16 near the iddle; the end orportion on one side of this shoulder having the opening 15 beingreceived in the groove 13. At 17 is a screw which passes through the hols 14 and 15 and is held fast by a nut 18, and the block 8 is providedwith a recess 19 which receives the nut 18. Thus the plate 7 and block 8are made rigid with each other and constitute a single unit. The block 8may be provided at one corner with a projection or nose 20. As

usual, the magneto of which this breaker is a part will be provided withcam projections in stationary position, and as the armature with thebreaker rotates, the nose 20 will strike 3 these cam projections, withthe result that the breaker lever is moved to separate the electrodes 5and 6. As shown in Figs. 1 and 4, the journal 9 is provided with ashoulder 21, against which the block 8 fits.

The screw 4 and electrode 5 are, of course, electrically connected tothe disc 1 but the metal plate 7 and electrode 6 are insulated. Toconnect the electrode 6 in the circuit of the armature, I attach to thedisc 1 a contact piece 22. Between this contact piece 22 and the disc 1is interposed a sheet of insulation 23, and the piece 22 has aprojection 24 extending away from the disc 1. To this projection isscrewed one end of a curved spring 25. The opposite end of this springis attached to the out-er end of the plate 7 by means of a rivet 26.W'ashers 27 may be employed in connection with this rivet on both facesof the plate 7, and the electrode 6 is a '1 part of this rivet. Toattach the spring 25 to the projection 24, I may employ a rivet 23, or ascrew, or any other suitable means. The contact piece 22 and theinsulation 23 may have registering openings 29 in line with the bore ofthe hub 2 and when this hub is mounted on the end of the armature shaft,a stem or bolt having a head thereon may be thrust through the openings29 until the head of said stem abuts the outer contact face of the piece22. The inner end of the stem will engage a suitable metal part by whichconnection is made with the armature winding; and thus through thisstein, which is not shown, a circuit is completed from one end of thearmature winding to the piece 22, and

- through the spring 25 to the electrode 6, electrode 5 and the framework of the magneto to the opposite or grounded terminal of the armaturewinding. Normally, this circuit is kept closed by the spring 25, butwhenever the 1 nose 20 strikes one of the cam projections abovementioned, the circuit will be opened and sparking will take place.

To secure the contact piece 22 in place, I may utilize a screw or rivet30 which passes through the contact piece 22 and the insulation 23, andis held fast to the disc 1. The hole in the piece 22 through which therivet 30 passes will be larger than the thickness of this rivet, andbetween the head of this rivet and the contact piece 22 is an insulatingwasher 31. Hence this rivet does not make contact with the piece 22. Thehole for the rivet 30 through the contact piece may be of the sizeindicated at 32 on Fig. 4, and the larger holes for the rivet throughthe insulation 23 and disc 1 are indicated at 33 on this figure. Theholes shown in Fig. 4 are additional holes for the double purpose offurther securing the contact piece 22 and attaching to the disc 1 a post34 having a shank 35 of less thickness than the width of the hole 32.This shank passes through the holes 32 and 33, and its end is expandedor riveted, attaching it permanently to disc 1 the same as with therivet 30. Between the post 34 and theend shoulder thereof from which theshank 35 projects, is an insulating washer 36 which is held by the post34 tightly against the contact piece 22, so that there is no metallicconnection between the post 34 and the contact piece 22. This post andthe rivet 30 thus bind the contact piece 22 and disc 1 together.

To the outer end of the post 34, I attach a spring 37 to serve as aholding element for the block of insulation 8. A screw or rivet 38anchors the spring 37 to the post 34 and permits the spring to be swungabout this rivet as an axis. The opposite end of the spring 37 has aprojection 39 and this end is bent slightly further away from the disc1, so that, while it passes over the edge of the spring 25, it does nottouch this spring. At 40 is a cap having a recess 41 in one face,

and a projection 42 on the opposite face. This cap closes the outer endof the bore 12. and the projection 42 enters this bore, so that the capcovers the end of this bore and the end of the journal 9 therein. Thespring 37 is so set that the-projection 39 enters the recess 41 in thecap 40 and exerts enough pressure on this cap to keep it in place.Hence, the block 3 and the interrupter lever are forced against theshoulder 21 and kept in position when the magneto is in operation; andby pulling the end of the spring with the projection 39 away from theblock 8, this holding spring can be swung to one side so that the cap 40can be taken off, and then the entire interrupter lever can be removedfrom the journal 9.

The disc 1 may also be provided with an integral hollow socket 43 whichopens through the same face on the disc as the hub 2, and in this socketis the usual spring-pressed ground brush 44 to rub upon the end plate ofthe magneto while the breaker is rotating, and give an eflicientconnection through the frame work of the magneto to the groundedterminal of the armature winding.

The breaker is thus seen to be made up of parts which can be very easilyshaped and fitted together and which can further be very readilydismounted when the breaker is in need of adjustment or repair, orwhenever any part needs to be replaced. The relatively fixed contact isthe grounded contact 5, and the electrode 6, which is movable, isinsulated from the body of the interrupter or disc 1, and therefore fromthe framework of the magneto, but is nevertheless connected in circuitwith the armature through the spring 25, which normally holds electrodes5 and 6 together. This spring, directly attached to the projection 24 ofthe contact piece 22, is electrically united by the stem (not shown),that engages the contact piece 22 and goes through the hub 2 into thearmature shaft to make connection with the armature winding. The entireassemblage is thus very compact and 25 very eflicient in practice.

Having described my invention, what I claim is:

1. A circuit interrupter comprising a supporting member of electricallyconductive material having a perforated projection, a fixed contact heldby said projection in circuit with said member, a contact piece securedto said member, insulation separating said piece and said member to keepsaid piece out of electrical connection therewith, said piece having aprojection and said member a journal, a block of insulation pivoted onsaid journal, a metal plate bearing a cooperating contact aflixed tosaid block, and a spring attached to said plate and the projection onthe contact piece and normally actuating the iplate to keep saidcontacts in engagement with each other.

2. An interrupter comprising a supporting member of electricallyconductive material, a fixed contact on said member and in circuittherewith, the latter having a ournal, a lever made up in part of aninsulating block having a bore receiving said journal to mount saidlever, a contact carried by the lever,

means insulated from said member for establishing connection with thelast named contact and acting normally to hold said contacts inengagement with each other, a post secured to said member and insulatedfrom the contact on the lever, a spring pivotally secured to said post,and a cap for engaging the lever adjacent said journal and to be pressedupon by said spring for detachably holding the lever in place on saidjournal.

In testimony whereof I affix my signature.

WOLFGANG E. SCHWARZMAN.

